‘Looper’ star Joseph Gordon-Levitt leaks some spoilers [VIDEO]

After first teaming up on the high school noir “Brick,” actor Joseph Gordon-Levitt and writer-director Rian Johnson are back together for the mind-bending science-fiction flick “Looper.” Gordon-Levitt stars as a man who works as a time travel-assisted hit man for the mob who one day is confronted with a challenging target: his older self, played by Bruce Willis. While the film doesn’t reach theaters until September, the pair hit WonderCon — Comic-Con’s younger brother — to begin the careful campaign of building interest in their new film.

You’re bringing a movie like this to WonderCon, but obviously you don’t want to give away too much about it. What’s the fine line you walk to generate interest without giving too much away?
Rian Johnson: We were just having this conversation on the elevator, so we’ll test it out on you. I don’t know, it’s weird because when you first start talking about a movie you have to figure out what to say and what to not say — especially with something like this. We’re showing the first teaser trailer here and releasing a photo, and one of the big elements of the movie is how we made Joe into a younger version of Bruce Willis. I feel like that’s kind of the first big thing we’re showing people, how we attempted that. The two big elements of that were makeup and Joe’s performance.

How much of a challenge was that for you, Joe, being turned into a young Bruce Willis?
Joseph Gordon-Levitt: It’s kind of a dream. One of the things — if not the thing — I love about acting is becoming somebody else, and when you literally change your face that’s a transition that’s different from any other performance that I’ve ever done in my life. So there was the makeup, and then also just hanging around with Bruce, getting to know him, watching his movies and studying them, listening to his voice on my iPod all the time, developing that character. It was really fun. It’s a really fun way to approach an acting job.

It must be interesting walking around with Bruce Willis’ voice in your ear all day.
JGL: Interesting is maybe not the word I would use. (laughs)

Was the plan always to have two actors for the older and younger versions of the character?
RJ: Initially when I cast Joe, before we had cast Bruce, we were talking about the option of just either doing makeup or doing something…
JGL: And I, the egotistical actor, was going, “Let me do both! Let me do both!” (laughs) I’m so glad that’s not what we did.
RJ: The reason I actually came down against it was twofold. First, aging makeup on younger actors — I don’t feel like I’ve ever seen it completely work. There’s been some tremendous work that’s been done, but I feel like if you know what an actor looks like who’s young, at least I as a moviegoer can usually see right through it. The bigger thing, though, a big part of the hook of the movie for was the idea of a young man sitting across from an older man who’s himself. You can make someone up, Joe is a fantastic actor, but there is something about a span of 25 years between two people that you can’t fake, that just buys you something that’s intangible and very essential to what this movie is basically about.

OK, but why not go the other way and try to make Bruce Willis look like an older Joseph Gordon-Levitt?
RJ: We kind of figured Joe would be more up for three hours in the makeup chair than Bruce.